1. Field of the Invention
The present invention relates to an image forming apparatus having a belt-like conveying section, a belt-like intermediate transfer body, and the like.
2. Description of the Related Art
Conventionally, there has been known an image forming apparatus adapted to form a color image. Such image forming apparatus has four image forming units for forming a toner image of yellow (Y), a toner image of magenta (M), a toner image of cyan (C), and a toner image of black (K). In each image forming unit, a photoreceptor is electrically-charged and then the electrical charges are erased according to a document image (i.e., the photoreceptor is so-called exposed), so that an electrostatic latent image is formed on the photoreceptor. Further, a developing section is used to cause the toner to adhere to the electrostatic latent image of the photoreceptor, so that a toner image is formed on the photoreceptor.
The toner adhering to the photoreceptor of each image forming unit is primarily transferred to, for example, a belt-like intermediate transfer body and then secondarily transferred to a sheet. The intermediate transfer body (sometimes referred to as “belt” hereinafter) is wrapped around a plurality of rollers. It is preferred that when transferring toner, a suitable transfer nip is formed between the photoreceptor and the belt-like intermediate transfer body.
Japanese Unexamined Patent Application Publication No. 2011-33740 discloses an art in which, in order to suppress separation of an intermediate transfer belt from image carriers to thereby prevent primary transfer failure and obtain a high-quality image, the transfer nip between the intermediate transfer belt and each of the image carriers is provided with a clown-like pressing member on the downstream side at a position near the transfer nip. By using the pressing member to press the intermediate transfer belt toward the side of each image carrier, the primary transfer pressure near the center of the intermediate transfer belt in the width direction can be prevented from dropping even in the case where two ends of the primary transfer roller in the axial direction are pressed toward the image carrier by a spring or the like. Thus, it is possible to form a transfer nip having a uniform primary transfer pressure in the axial direction of the primary transfer roller.